Random House, the world's largest book publisher, expects electronic book sales to contribute over 10 percent of its revenue next year, CEO Markus Dohle announced Sunday.

Dohle told German magazine Der Spiegel that e-book revenue had already increased to 8 percent in the US.

Amazon's Kindle, the latest of which launched last week, and Apple's iPad have created a massive market for e-books. Amazon has already reported that e-books are outselling hard-cover books.

Dohle, however, does not believe e-books will replace printed books in the next five years.

Random House does not currently offer e-books for the iPad; Dohle said he was not yet certain about Apple's device, which forces publishers to determine the end-consumer price, unlike printed books, whose costs are determined by retailers.